import java.sql.*;

public class Example01 {
    public static void main(String[] args) throws SQLException {
        /** JDBC连接数据库
         * 1. 加载 驱动
         * 2. 连接
         * 3. 表结构-预处理(SQL)
         * 4. 执行SQL语句
         * 5. 结果
         * 6. 释放 连接
         */
        /**
         * (1) 加载
         * a. 根目录创建lib文件夹
         * b. 将连接的jar包放入lib
         * c. 点击 文件->项目结构->模块->依赖->+号->JAR或目录->选中mysql的jar包
         * d. 编写加载代码
         */
        Statement stmt = null;
        ResultSet rs = null;
        Connection conn = null;
        try {
            // 1. 注册数据库的驱动
            Class.forName("com.mysql.cj.jdbc.Driver");
            // 2.通过DriverManager获取数据库连接
            String url ="jdbc:mysql://localhost:3306/jdbc" +
                    "?serverTimezone=GMT%2B8&useSSL=false";
            String username = "root"; //数据库账户
            String password = "root";
            conn = DriverManager.getConnection(url, username, password);
            // 3.通过Connection对象获取Statement对象
            stmt = conn.createStatement();
            // 4.使用Statement执行SQL语句
            String sql = "select * from users";
            rs = stmt.executeQuery(sql);
            // 5.操作ResultSet结果集
            System.out.println("id |  name |  password" + "|   email   |  birthday");
            while (rs.next()) {
                int id = rs.getInt("id"); //  通过列名获取指定字段的值
                String name = rs.getString("name");
                String paw = rs.getString("password");
                String email = rs.getString("email");
                Date birthday = rs.getDate("birthday");
                System.out.println(id + "  |  " + name + "  |  " + paw +
                        "   |  " + email + "   +  birthday");
            }
        }catch (ClassNotFoundException e) {
            e.printStackTrace();
        } finally {
            // 6.回收数据库资源
            if (rs != null) {
                try {
                    rs.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
                rs = null;
            }
            if (stmt != null) {
                try {
                    stmt.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
                stmt = null;
            }
            if (conn != null) {
                try {
                    conn.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
                conn = null;
            }
        }
    }
}
